Difficult canine vomiting cases (Proceedings)
A common and often frustrating problem encountered in small animal medicine is chronic vomiting. Chronic gastrointestinal disease in young animals is often caused by parasitism, dietary indiscretion, congenital disease (megaesophagus), and breed-associated diseases, whereas disease in the older animal is often a result of neoplastic and infiltrative disease. The etiology may be discovered while taking a complete history or during a complete physical examination (or maybe the 3rd or 4th complete physical examination). However, in most cases additional diagnostics, some of which are maximally invasive, are necessary.
Although most cases are not solved with the history, the clinician can obtain valuable information that may help narrow the scope of diagnostics. The history will help identify or define the chief complaint, the frequency and severity of disease, the character of the vomitus, and success or failure of previous therapies. Changes in diet, administration of other drugs, recent or frequent kenneling, environmental changes, and health of other animals in the household may offer additional clues. The history should help discriminate vomiting from regurgitation. In some cases, however, the history can be confusing and fail to provide significant differentiating information.Physical examination
The important components of the physical examination to remember are:
1. Abdominal palpation: it can not be emphasized enough the importance of a thorough, deep, and patient abdominal palpation. Identification of a focal mass makes endoscopy a less useful tool, whereas diffusely thickened intestines often are caused by a disease that can be diagnosed at endoscopy. The other points to remember are to always repeat the abdominal palpation carefully at each recheck examination, and always palpate the abdomen when the patient is anesthetized (e.g. for endoscopy, oral examination, etc.).
2. Rectal palpation: obviously important for evaluating for possible masses or strictures when tenesmus or constipation is present, it is equally important in patients with chronic diarrhea and vomiting. Sample for fecal flotation and fecal smear can be obtained and a rectal scrape can be performed to look for fungal organisms or lymphoma.
3. Ocular examination: although usually low yield, cats with FIP may have ocular lesions, dogs and cats with dysautonomia may have dilated, nonresponsive pupils and poor tear production, and fungal lesions may also be seen.
4. Neurological Examination: carefully evaluate the cranial nerves, as deficits may suggest the presence of an intracranial mass as the cause of chronic vomiting.
After obtaining the history and performing the physical examination, the clinician will often have a "gut feeling" as to the most likely diagnosis. The dog with chronic vomiting that has not lost any weight and still seems bright and alert rarely has gastric neoplasia, the goofy Labrador retriever that has a history of eating everything in the world might very well have a foreign body, and the emaciated dog with anorexia and hematemesis may have gastrointestinal neoplasia. Although this impression can often times be correct, the prudent clinician will always do an appropriate work-up. Never forget that there are systemic diseases that can cause chronic vomiting and many of these can be identified on routine laboratory work. The initial minimum data base should include a complete blood count (CBC), serum biochemistry profile, urinalysis, and fecal flotation. Although the CBC and serum biochemistry profile provide very little information as to primary GI disease, they are important in identifying non-GI disease. It is important to point out that eosinophilia is not a common finding in dogs or cats with inflammatory bowel disease. Some systemic causes of chronic vomiting include:
1. Chronic renal failure: particularly in cats who can survive CRF for much longer than dogs. The diagnosis is usually straightforward with the finding of azotemia, isosthenuria, and small kidneys. Administration of H2 blockers, metoclopramide or cisapride, control of hyperphosphatemia, and control of metabolic acidosis may decrease the incidence of vomiting.
2. Hypoadrenocorticism: this is a frequently misdiagnosed cause of chronic vomiting and diarrhea, particularly in middle-aged female dogs. The diagnosis should be suspected in any dog with a waxing and waning history of signs. Common laboratory abnormalities are hyperkalemia, hypokalemia, lymphocytosis, and mild azotemia. The disease can be confusing in the patient without electrolyte abnormalities. You can never do enough ACTH stimulation tests.
3. Hepatic disease: although usually suggested by elevated liver enzymes, hypoalbuminemia, and low BUN, some patients may not have all of these changes. Hepatic dysfunction can be identified with a bile acids test. Microhepatica seen on radiographs should alert the clinician.